Copper base alloy



Patented Jan. 14, 1936 COPPER BASE ALLOY Henry 1.. Burghofl, Yalesville, and David E. Lawson, Waterbury, Coma, assignors to The Chase Coiilpanies, Incorporated, Waterbury, Com, a

corporation NoDrawing. Application May 13, 1932, Serial No. 611,238

11 Claims.

This invention relates to improvement in copper-base alloys, that is to say, alloys inwhich copper is the major constituent, and has for its main object the improvement of the physical properties of such alloys, as will hereinafter appear.

We have discovered that by including relatively small quantities of tellurium in copper-base alloys, such as ordinary brasses, aluminum brasses,

grain growth and thus serves to provide in the metal a grain structure materially smaller than would ordinarily be the case, were the tellurium absent. Our investigations have shown that the tellurium has no appreciable "effect on the temperature of incipient recrystallization, or, in other words, the tellurium does not raise the temperature of initial softening. The tellurium has, however, a very marked effect on the rate of 20 grain growth after recrystallization, inasmuch as it acts, as above pointed out, as an inhibitor, tending to prevent grain growth, which ordinarily accompanies high temperature annealing. It will thus be seen that the tellurium imparts to the metal highly desirable characteristics of softness and ductility without, however, producing an unduly-coarse crystal or grain structure which would be objectionable for many finishing operations. With the smaller grain size, due to the presence of tellurium, lower finishing costs result.

We have also discovered that by including tellurium in. copper-base alloys, the modulus of elasticity of the same may be lessened to a degree sumcient to render the material more flexible than would otherwise be the case where such a quality is desired.

Furthermore, we have discovered that by combining tellurium with certain copper-base alloys, the machinability of such alloys is distinctly improved. Thisimprovedmachinability oftelluriumbearing copper alloys is evidenced in several ways, such, for instance, as during a. sawing operation at which time it will be found that such alloys out easily and rapidly with substantially no tendency to seize or bind. When being drilled, these alloys cut rapidly and cleanly and the cut chips do not, clog the drill. By way of illustration, .it may be stated that it was found that anaveragecf seventy cuts of a power-saw were'required to sever a rod composed'of 90% copper and zinc. while only thirty-five saw-cuts were required to sever a similar rod composed of 89.8% a

mm, required seventy-nine saw-cuts to be sevtin bronzes, etc., the tellurium serves toinhibitered, while a substantiallyrsimilar rod containing for the same operation.

Practically all types of machining operations may be performed upon our improved alloy without occasioning appreciable chattering or vibra- .0.2% tellurium required only forty-six saw-cuts tion, though as might be expected, the alloy beoperations.

Our improved alloy is characterized by a pre- 4 ponderance of copper and from 0.08% to 1.75% inclusive of tellurium, together, if desired, with other elements such, for instance, as zinc, tin,

aluminum, nickel, cadmium, manganese, silicon,

cobalt, etc.

Preferably, our improved alloy should contain between 0.20% and 0.50% tellurium, as we have found that within that range the alloy possesses most of the desirable physical properties without undue brittleness, though as before pointed. out, we have found that a copper-base alloy containing from 0.08% to 1.75% tellurium possesses marked advantages over similar alloys containing tellurium in amounts outside the last-mentioned range.

The following table sets forth alloys which are illustrative of some of the various combinations of materials in accordance with our invention:

A B O D E F G Copper 66.00 95.00 80. 00 92.00 98.80 96.80 90. 00 Tellurium 0.30 0. 20 0. 50 0. 50 0.10 0. 10 0. 50 Zinc 43. Tin 4. 73 Aluminum 7. 42 Nickel 19. 40 Cadmium 1.00

Manganese 9. 40 Silicon 3.00 Misc. 0.10 0.07 0. l0 0. 08 0.10 0. 10 0. 10

Microscopic examination has shown that in most of the alloys above mentioned, the tellurium is present, largely at least, in a second phase from 55 the usual alpha phase of high-copper alloys. This second phase probably contains some form of copper-telluride.

In making up our improved alloy, any of the well-known methods of combining the constituent parts may be employed such, for instance, as by directly adding the tellurium or by first alloying the tellurium with one or more of the components of the material in question to produce a high tellurium-content alloy for later dilution.

Although reference is made herein to certain specific alloys, it is to be understood that our invention is not limited to the proportions recited, but only to the proportions set forth in the appended claims.

We claim: I

1. A ductile copper-base alloy comprising copper and tellurium, with the copper content being at least 75% and the tellurium being present in an amount from 0.08% to 1.75% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

2. A ductile copper-base alloy comprising copper and tellurium, with the copper content constituting 90% or more of the combined copper and tellurium, and the tellurium being present in an amount from 0.08% to 1.75% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

3. A ductile copper-base alloy comprising copper and tellurium, with the copper content constituting 90% or more of the combined copper and tellurium, and the tellurium being present in an amount from 0.20% to 0.50% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

4. A ductile copper-base alloy comprising copper, a minor amount of zinc and tellurium, the copper content being more than 50% and the tellurium being present in an amount from 0.08% to 1.75% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

5. A ductile copper-base alloy comprising cop- ,per, a minor amount of zinc and tellurium, the

copper content being more than 50% and the tellurium being present in an amount from 0.20% to 0.50% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

6. A ductile copper-base alloy comprising copper, a minor amount of tin and tellurium, with the copper content being more than 50% and the tellurium being present in an amount from 0.08% to 1.75% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

7. A ductile copper-base alloy comprising copper, a minor amount of tin and tellurium, with the copper content constituting 90% or more of the combined copper and tellurium, and with the tellurium being present in an amount from 0.20% to 0.50% inclusive, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

8. Copper or copper base alloys containing from approximately .1% to 1.75% of tellurium and being characterized by substantially improved machinability over that which would exist in the absence of said tellurium.

9. An alloy of copper and silicon containing from approximately .08% to 1.75% of tellurium and having a silicon content of approximately 3% and the balance substantially copper, the said alloy being characterized. by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

10. A copper-base alloy containing more than 75% copper, silicon, and approximately 0.08% to 1.75% tellurium, the said alloy being characterized by substantially improved machinabillty over what the alloy would possess in the absence of said tellurium.

11. A copper-base alloy containing more than 90% copper, approximately 3% silicon, and approximately 0.08% to 1.75% tellurium, the said alloy being characterized by substantially improved machinability over what the alloy would possess in the absence of said tellurium.

HENRY L. BURGHOFF. DAVID E. LAWSON. 

